Page 328 of 378 Maintenance
553-3001-202 Standard 1.00 April 2000
DCH link failu re
The DCH link can change to the RLS (re lease) state due to technician action
in LD 96, MSDL or SDI/DCH card failure, or cable failure. Thi s condi tion is
detected on the DCHIP card by the PC Card signaling th at the L2 conne ction
has failed.
PC card failu re
The PC card failure can be detected in various ways, through
• missing heartbeat transmission
• a hardware interrupt
When the software does not send “an activity test message” (heartbeat
message) to the Card Services of the PC Card Device Driver during a period
greater than n seconds, Card Servic es consid er it a breakd own detect ion. Car d
Services tries to reset the PC Card. Card Services are responsible f or making
sure of the conformance of the reset timing. Card Services also check and
wait for the card to reach the READY state.
Socket Services are responsible for card insertion and removal. There is a
single interruption shared for insertion and removal events and a single
interruption for device specif ic i nte rrupt ions. Socke t Ser vic es ide nt ify whi ch
socket originates the interruption and sends the interruption to the Card
Services interruption handle r . Card Services then wait and re - initialize the
PC Card, if the card is plugged in again and is in the READY state.
Do not insert or remove the PC Card when the ITG card is plugged in.
DCHIP card failure
This occurs when the DCHIP ITG card goes out of service. The DCHIP ITG
card failure case is similar to the DCH l ink f ailure case. However, all call
reference information is gone. As a result, when the DCHIP comes back up,
it sends a “REStart” message to the other side to re - initial ize all the trunks.
All the established calls are cancelled.
Power loss
Since the ITG card is based on Flash EPROM technology, all configuration
data is preserved for 10 years. There is no requirement for a battery backup
for the card. The ITG card can be removed from the IPE shelf indefinit ely and
still retain all configuration data.